Find out how many inboxes and sending domains you need to hit your target daily volume safely — and roughly how long warmup takes before you can send at full speed.
Planning estimate, not a deliverability promise. Safe limits vary by domain age, warmup, and list quality. Runs in your browser only.
To find how many inboxes you need for cold email, divide your target daily send volume by a safe per-inbox limit (many senders keep this around 30–50 emails per inbox per day to protect reputation), then divide the inbox count by how many inboxes you run per domain (commonly 2–3). For example, to send 500 emails/day at 40 per inbox you'd need about 13 inboxes, spread across roughly 5 domains. New inboxes also need a warmup ramp (often a few weeks) before sending at full volume. The calculator below works this out from your own numbers.
Sending too much from one inbox or one domain is a fast way to hurt deliverability and land in spam. Spreading volume across many inboxes (each under a safe daily limit) and across several domains keeps any single sender's reputation healthy and limits the blast radius if one domain has an issue. The calculator turns your target volume into the inbox and domain counts that keep you under those safe limits.
A brand-new inbox can't send hundreds of cold emails on day one without tripping spam filters. Warmup gradually increases sending and simulates real engagement so mailbox providers build trust in the sender. Plan for a ramp (often a few weeks) before each new inbox reaches full volume, and stagger new inboxes so you're not warming everything at once.
Exact safe limits depend on domain age, warmup quality, list accuracy, and the mailbox provider. Treat the output as a conservative starting plan. The cleaner your list and the better your warmup, the more headroom you have — but it's far cheaper to over-provision inboxes slightly than to burn a domain by over-sending.
Divide your target daily volume by a safe per-inbox limit. If you keep each inbox to about 40 emails a day and want to send 500 a day, you'd need roughly 13 inboxes. Lower the per-inbox limit (more conservative) and you'll need more inboxes; the calculator on this page computes it from your numbers.
Take your inbox count and divide by how many inboxes you run per domain — commonly 2–3. So 13 inboxes at 3 per domain is about 5 domains. Spreading inboxes across multiple domains protects deliverability and contains risk if one domain has a reputation problem.
Many senders keep new or cold-sending inboxes around 30–50 emails per day to protect reputation, ramping up only after a solid warmup and with a clean list. The right number depends on domain age, warmup, and list quality, so treat 30–50 as a conservative default and adjust based on your own deliverability data.
Yes — that's a core part of the platform. Instead of buying and wiring up domains and inboxes yourself, JYNI can send cold email from managed sender domains with warmup and CAN-SPAM compliance handled, alongside lead discovery and a CRM. This calculator is free to use either way.
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